Cars would be out of place, but it would be cool.
I was thinking about an MI ride. You could start off on a suspended door. You would take a seat and pull down the lap bar. Attached to the lap bar is your flashlight ala TSM. The first part of the ride would be like Ride and Go Seek. Then something goes hprribly wrong and you are whisked into the door vault for the rollercoaster portion. I imagine the door scene would be on a much grander scale than at the MI ride at DCA. It may have dark ride scenes where you go through the different doors in the vault. It would be awesome if the ride would go faster based on the guest's screams. Eventually, you go back into the factory for one last round of flashlight tag before exiting by a Roz animatronic.
An attraction with that much technology could easily challenge Potter and would fit perfectly with Monsters University coming out in 2013.